Adding and Subtracting Fractions (ppt)

Adding and Subtracting
Fractions with
Pictures
&
Numbers
By Kathy Woodard 2012
Write with the same denominator:
1.
3

3.
4
2.
2
Write with the same denominator:
3
4.
12
5. Simplify this expression:
2(3  1)

2
12

1
5

6
6. Put in descending order:
2
7 7
2
0
100% ,
6
5
,
5
6
Key Words
Add put different things
Subtract take away, OR
together: sum, total, in all,
combined, earn money, increase
find how much is left after, OR
comparing how much more/less:
difference, how much more, take
away, give away, spent, decrease,
money off of the price
Multiply put same-size
Divide cut into same-size
things together:
# of, groups of, area (length x
width), doubled = x2, tripled = x3
groups: how many groups, the
line in a fraction says divide, per,
Round finding what it is close to:
closest to
about, estimate, approximately,
Add or Subtract?
David measured 3/8 inch of rain Monday.
He emptied the rain gauge and then
measured 7/8 inch more rain on Tuesday.
How much rain fell on both days
combined?
Add or Subtract?
David measured 3/8 inch of rain Monday.
He forgot to empty the rain gauge. By
Tuesday night there was 7/8 inch rain in
the rain gauge. How much rain fell on
Tuesday?
1. Add or Subtract?
Jill and Sarah went panning for gold. Jill
found 7/10 g of gold and Sarah found
6/10 g of gold. How much more gold did
Jill find than Sarah?
2. Add or Subtract?
Jill took her 7/10 g gold to the goldsmith
and had jewelry made. The jewelry used
3/10 g of gold. How much gold was left
over?
3. Add or Subtract?
Hermione wants to use ribbon to make a
border for her quilt. She has three pieces
of ribbon: the first is 5/6 ft, the second is
4/6 ft, and the third is 3/6 ft. How long of
a quilt border can she make?
4. Add or Subtract?
Before Thanksgiving dinner we had a
whole pumpkin pie. We ate 5/9 of the pie.
How much pie do we have left?
When you add or subtract fractions they
have to have the
same denominators.
2
7

3
7

3
8

1
6

Try Together
5. Addition or Subtraction?
Tia and Mark each bought a chocolate
bar. Tia ate 2/3 of her candy bar, and
Mark ate 1/6 of his candy bar. How
much more did Tia eat than Mark?
6. Addition or Subtraction?
4
5
Muffin the kitten weighed kg when she
1
2
was born. She has since gained kg.
How much does she weigh now?
7. Add or Subtract?
Jo has 2/3 of a yard of yarn and Kia
has 1/4 of a yard. They need 1 yard
for their project. Do they have
enough?
8. Addition or Subtraction?
Before Jeni started cooking she had 3/4 lb of
chocolate chips. After she finished there was
only 1/3 lb of chocolate chips left. How many
pounds of chocolate chips did she use?
9. Addition or Subtraction?
Rita drank 1/6 cup of lemonade.
Then she drank 1/2 cup of water.
How much liquid did Rita drink?
10. Addition or Subtraction?
5
6
Joe had L of motor oil, but then he
1
2
used L to fill up his engine. How much
oil does Joe have left?
11. Add or Subtract?
12. Your Turn:
One of Mrs. Woodard’s cookie recipes calls
for 1 3/4 cups of flour. The other recipe
calls for 2 3/4 cups of flour. How much
flour will she need to make both recipes?
13. Don’t forget to simplify:
Mina
Mina
14. Addition or Subtraction?
Abby buys 5 1/2 pounds of apples. She
uses 2 1/4 pounds to bake a pie. How
many pounds does she have left?
15. Addition or Subtraction?
Tim mails two boxes of cookies to friends.
One box weighs 1 3/4 pounds and the other
weighs 2 2/3 pounds. What is the total
weight of the two boxes?
16. Addition or Subtraction?
Paul is 6 ¼ feet tall. Kathy is 5 ¾
feet tall. How much taller is Paul than
Kathy?